The definitive how-to install the valve cover and gasket

NobleHops · Post by **NobleHops** » Sun Apr 04, 2010 10:36 pm

...I need one, that is

I can't seem to get it to seal.

I think for starters I'm reusing one that needs to get retired, so a new one is on order. So far I tried gluing the gasket in to the channel with a bead of RTV and I could not get it to stick, despite having meticulously cleaned out the channel and cleaning and drying the gasket thoroughly. I think the RTV is just too thick and that's causing problems too.

I switched-up to some Permatex high-tack gasket sealer, same problem.

I've got a third adhesive that works like contact cement, is applied to both surfaces, you let it set up, then apply. I'm thinking I'll try this next with a new gasket, plus the prescribed dab at the corners of the cam end cap disks.

Am I on the right track? What's the secret sauce here?

TIA,

N.

daves79x · Post by **daves79x** » Mon Apr 05, 2010 5:25 am

Nils:
I use HondaBond or YamaBond crankcase sealant. I think there is still some oil residue either on your gasket or cover channel or both. Any of the stuff you've tried should have worked. Try cleaning everything with brake cleaner.

Dave

EMS · Post by **EMS** » Mon Apr 05, 2010 7:35 am

If the rubber seal is good, the valve cover should not need any additional sealer other than a small dab in the corners where the cam end covers sit.
Most leakage problems are due to old and hardened rubber seals that are no longer pliable.
Be very careful to not overtorque the bolts, if you strip the threads in the cam towers, you are in trouble....

daves79x · Post by **daves79x** » Mon Apr 05, 2010 2:15 pm

Mike:
I think we are talking about how to glue the gasket to the cover to keep it in place during installation. The places you mentioned need sealant for actual sealing purposes.

Nils:
Make sure your grommets on the hold-down bolts are nice and soft. If not, they will leak. You can replace them as needed with the engine in place.

Dave

NobleHops · Post by **NobleHops** » Mon Apr 05, 2010 2:30 pm

daves79x wrote:Mike:
I think we are talking about how to glue the gasket to the cover to keep it in place during installation. The places you mentioned need sealant for actual sealing purposes.

That was needed info too!

Nils:
Make sure your grommets on the hold-down bolts are nice and soft. If not, they will leak. You can replace them as needed with the engine in place.

Dave

Thanks Dave. I do have new grommets in there, can't recall where I sourced them, but they are smaller in diameter than the ones they replaced.

My gasket is pretty hard, so I will wait till my new one is here, clean the channel in the cover within an inch of it's life, glue it, dab the sealant where indicated, and go for it. Some older posts revealed two other helpful tricks that I will employ as well:

One by my friend Steve G said to put a jack under the engine and remove the second smaller set of engine hanger brackets, let the engine down a skosh, and pick up a couple of helpful millimeters of clearance in the process.

The other suggested the use of a spatula to hold the gasket in place from the rear as the valve cover is worked over that high oil pipe that gives the clearance trouble.

I will reply with a wrap-up when I figure out what works for me.

N.

daves79x · Post by **daves79x** » Mon Apr 05, 2010 4:11 pm

Nils:
It sounds like you have grommets for the '79 model only. The '80-'82s take a larger grommet and the bolts are a bit longer in the shoulder as well. Also, the flat surface is broader on the valve cover to have more sealing area. Not sure how the smaller grommets will seal.

Steve's tip will give the added clearance you need for sure.

Dave

NobleHops · Post by **NobleHops** » Mon Apr 05, 2010 5:22 pm

daves79x wrote:Nils:
It sounds like you have grommets for the '79 model only. The '80-'82s take a larger grommet and the bolts are a bit longer in the shoulder as well. Also, the flat surface is broader on the valve cover to have more sealing area. Not sure how the smaller grommets will seal.

Steve's tip will give the added clearance you need for sure.

Dave

Bill Brint shed more light on this just now. It seems that I have an 81 or 82 valve cover, based upon the larger flat surface on the valve cover. According the Bill, the 79 and 80 valve covers (and grommets) are identical, and the 81 82 are the larger. In any event, I have the larger, and I had larger grommets before I swapped in these newer smaller ones. I did not think it would make a difference.

As I said to Bill, I have to learn everything the hard way sometimes. I don't think I have done anything once in this project. If I did this for a living I would starve. You guys that do this all the time have even more of my respect.

N.

EMS · Post by **EMS** » Mon Apr 05, 2010 7:01 pm

Funny thing is, the 1981 and 1982 parts list shows the mounting grommets as part-number 90543-422-003 (i.e.: the same as 1979) for all of 1981 and until engine No 2400815 for 1982. Only from 1982 engine number 2400816 does the rubber grommet change to 90543-MA2-000.
While the valve cover is the same for 81 and 82.
Wonder what problems all the guys - including myself - who still have the original grommets on their 81s and early 82s have?
Maybe Bill Brint knows?

Jeff Bennetts · Post by **Jeff Bennetts** » Mon Apr 05, 2010 7:42 pm

Thats interesting, I have never worked on a late model that had the smaller grommets, I'll have to pay more attention to that when I'm around them.

daves79x · Post by **daves79x** » Mon Apr 05, 2010 7:47 pm

Hate to tell you guys, but Bill is wrong! The '80s also had the large hold-down grommets. The superseeded grommet part #s are ALL the same for the '80-'82. ONLY the '79s are different. The '80-'82 valve covers are exactly the same except for being painted or polished. Trust me on this - I've been through it a hundred times.

Bill has sold some '80 restorations with '79 valve covers on them and even whole '79 engines. Look at the valve cover grommets and it's a dead giveaway. I begin to think they really do not know some of these fine differences in the various years. Don't get me wrong, they do nice work, and Bill is a good guy, but some of these incorrect details drive me nuts. Sorry for the rant.

Dave

NobleHops · Post by **NobleHops** » Mon Apr 05, 2010 7:56 pm

daves79x wrote:Hate to tell you guys, but Bill is wrong! The '80s also had the large hold-down grommets. The superseeded grommet part #s are ALL the same for the '80-'82. ONLY the '79s are different. The '80-'82 valve covers are exactly the same except for being painted or polished. Trust me on this - I've been through it a hundred times.

Bill has sold some '80 restorations with '79 valve covers on them and even whole '79 engines. Look at the valve cover grommets and it's a dead giveaway. I begin to think they really do not know some of these fine differences in the various years. Don't get me wrong, they do nice work, and Bill is a good guy, but some of these incorrect details drive me nuts. Sorry for the rant.

Dave

Bill is a great guy in my book, and I doubt he'd argue the point with you Dave, given your knowledge and experience. As my grommets are new he just said, 'send me yours and I'll swap you for the others'. And then he hurried off the phone so he could be certain to have it ready to go out tonight.

N.

daves79x · Post by **daves79x** » Mon Apr 05, 2010 8:15 pm

It's this simple guys - go to your Honda dealer and have them look up the part # for the '80 grommets (make sure THEY know what they are looking at), and compare that # with the '81-'82. They will show as the same #.

Also, look at any good photo of an original '80 CBX. I have all the period magazine tests and they all took endless photos of the engine, of course. They all have the large grommets on the hold down bolts. Once you see the difference in the two sizes, you can tell them apart a mile (not quite) away.

Will the smaller grommets seal on the later covers? Probably, for a while. I'm sure there are lots of '80-'82 CBXs running around out there that way and sealing OK, but it is not the way Honda built them.

In case you can't tell, this is one of my (many) pet peeves about CBX restorations.

There are over 100 differences between just the '79 and '80 models alone. This would be a good rally contest - see how many guys (and gals) can name.

Dave

EMS · Post by **EMS** » Mon Apr 05, 2010 9:04 pm

daves79x wrote:It's this simple guys - go to your Honda dealer and have them look up the part # for the '80 grommets (make sure THEY know what they are looking at), and compare that # with the '81-'82. They will show as the same #.

Dave

Well, Dave, while I share your doubts in Bill Brint as a reliable CBX authority, I am still not convinced. I looked at the same part-number list as any Honda dealer would. Unfortunately, I don't have a 80 parts list readily available, but my 81-82 list shows the grommet numbers that I quoted above, indicating the larger grommet came into use only during the 82 model year and the valve cover of the 81-82 being 12311-MA2-000. If it would be the same as the 80 cover, it would be a -469- part-number and the last three digits would differ for the paint. And I have not seen a stock CBX valve cover that was polished by the factory.

SteveG · Post by **SteveG** » Mon Apr 05, 2010 10:02 pm

Since I don't care about 100% authenticity and decal thickness, I sourced the smaller valve cover grommets for my '82 (because that is what I was able to find).

I then applied a thin coat of Honda Bond to the grommets (as well as the entire groove in the valve cover and the the head seating area (i.e. both sides of the gasket, but on the metal instead)) and haven't had a drip in 5,000 miles. Time again for the valve check and Honda Bond smear!!!

Steve

TerryL · Post by **TerryL** » Mon Apr 05, 2010 10:28 pm

In re: ..."haven't had a drip in 5,000 miles. Time again for the valve check"

You can wait much longer Steve. :)